Genetic Mechanisms of Resistance against Cardiac Preconditioning

心脏预适应抵抗的遗传机制

• 批准号: 8698274
• 负责人: Matthias L. Riess
• 金额: --
• 依托单位: CLEMENT J. ZABLOCKI VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8698274
• 关键词: ATP Synthesis Pathway; Affect; African American; Aging; Agonist; Attenuated; Binding Proteins; Blood Vessels; Calcium; Candidate Disease Gene; Cardiac; Cardiac Myocytes; Cardiovascular system; Cell physiology; Chromosomes; Chromosomes, Human, Pair 6; Complement; Complex; Coronary; DNA; Dahl Hypertensive Rats; Disease; Exhibits; Failure; Genes; Genetic; Genetic Models; Genetic Predisposition to Disease; Genotype; Goals; Heart; Individual; Infarction; Injury; Institution; Investigation; Ischemia; Ischemic Preconditioning; K-Series Research Career Programs; Measurement; Measures; Mechanics; Mediating; Medical; Membrane Potentials; Metabolic; Mitochondria; Modeling; Morbidity - disease rate; Muscle Cells; Myocardial; Myocardial Infarction; Myocardial Ischemia; Myocardial tissue; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Norway; Oxidation-Reduction; Oxidative Stress; PPAR gamma; Patients; Peroxisome Proliferator-Activated Receptors; Peroxisome Proliferators; Phenotype; Play; Population; Production; Rattus; Rattus norvegicus; Reactive Oxygen Species; Reperfusion Injury; Reperfusion Therapy; Research; Research Project Grants; Resistance; Role; Signal Pathway; Superoxides; System; Techniques; Testing; Tissue Viability; Variant; Ventricular; Veterans; Wisconsin; base; clinical practice; consomic; functional outcomes; helix-loop-helix protein differentiation inhibitor; human NOS3 protein; inhibitor/antagonist; medical schools; mortality; oxidation; preconditioning; prevent; protein expression; receptor; research study; resistance mechanism; resistant strain; salt sensitive; success; tool

DESCRIPTION (provided by applicant): As a VA anesthesiologist and physiologist I study protection against myocardial infarction, a significant medical problem in aging Veterans. In Ischemic Preconditioning (IPC), for example, several shorter ischemic periods before sustained ischemia/reperfusion (IR) attenuate infarction. Various triggering mechanisms have been described for IPC, including nitric oxide (NO) and superoxide formation. Genetic predisposition, however, may be an important confounding factor when trying to transfer it into clinical practice; while some patients may benefit others do not. Profound differences in ischemic tolerance exist not just among but also within certain species. For example, Dahl Salt Sensitive (SS) rats are more susceptible to IR injury than Brown Norways (BN), making them an ideal model to study the genotype of diseases phenotypically similar to African-American patients. In a unique chromosomal substitution (consomic) model constructed at the Medical College of Wisconsin introgression of BN chromosome 6 into SS renders the resulting SS6BN consomic more IR resistant while narrowing the genetic difference to a single chromosome. This offers an excellent starting point to study the genetic basis of cardioprotective strategies like IPC. Although NO has been implicated in decreasing infarct size in BN vs SS without IPC, it is yet unknown if SS can respond to IPC and if resistance to IPC is related to differences in endothelial NO synthase (eNOS) activity possibly modulated by the DNA-binding protein inhibitor Id2 and the peroxisome proliferator-activated receptor 3 (PPAR3). eNOS can produce NO or superoxide. Both can modulate mitochondrial function, which in turn can function as a trigger and effector of IPC. Thus, my overall hypothesis is that failure/success of cardioprotection by IPC is mediated by genes regulating NO production and mitochondrial function. I therefore propose to use this consomic model to study two specific aims: I) Determine if a different genetic background is responsible for differential cellular and mitochondrial protection by IPC, and II) if eNOS and/or its upstream modulators Id2 and PPAR3 are candidate genes responsible for this differential protection. Four hypotheses are tested: 1) Genes on BN chromosome 6 are necessary for IPC as evidenced by better cardiac function and less infarction in BN & SS6BN vs SS. 2) Genes on BN chromosome 6 are necessary for IPC as evidenced by more efficient mitochondrial function in BN & SS6BN vs SS. 3) Protection of cellular and mitochondrial function by IPC in intact hearts depends on the signaling pathway Id2->PPAR3->eNOS->NO modulated by genes on rat chromosome 6. 4) Differential protection of cellular and mitochondrial function in isolated cardiomyocytes depends on NO availability. Approaches for 1 & 2: Various cardiac and mitochondrial functions, NO production and infarct size are measured in intact, beating hearts to assess quantity and quality of genetically determined protection by IPC. Approaches for 3 & 4: Additional beating heart experiments are conducted in the presence of NOS inhibitors, an NO-donor, or a PPAR3 agonist or antagonist, and differences in Id2, PPAR3, and eNOS expression and NO levels and localization are determined. In addition, different mitochondrial functions in the absence or presence of NO are measured in isolated myocytes to determine the role and origin of NO in mediating differential cellular and mitochondrial protection by IPC in this genetic model. Genetic tools are essential to study the role of genetic predisposition. Correlating functional outcomes, infarct size, and mitochondrial functions with IPC, NO levels, protein expressions and genotype will allow us to define the signaling pathway and role of NO and mitochondrial function in cardioprotection and to delineate the subcellular and mitochondrial phenotypes associated with the cardioprotective genotype variation. This CDA marks the indispensable basis for further investigations on the role of genetics in cardioprotection and will be a critical milestone to achieve investigative independence in cardiovascular research at the VA.

描述（由申请人提供）： 作为VA麻醉师和生理学家，我研究了对心肌梗死的保护，这是老年退伍军人的重大医学问题。例如，在缺血性缺血/再灌注（IR）减弱梗塞之前，在缺血性预处理（IPC）中。已经描述了针对IPC的各种触发机制，包括一氧化氮（NO）和超氧化物形成。然而，在试图将其转移到临床实践中时，遗传易感性可能是一个重要的混杂因素。虽然有些患者可能会使其他患者受益。缺血性耐受性的深刻差异不仅存在于某些物种中，而且存在于某些物种中。例如，与棕色挪威（BN）相比，DAHL盐敏感（SS）大鼠更容易受到IR损伤，使其成为研究与非裔美国人患者表型相似的疾病基因型的理想模型。在威斯康星州医学院在BN 6染色体中构建的独特染色体替代（Consomic）模型中，SS的SS60亿SS60亿SSS60亿sss抗性更具耐酸性，同时将遗传差异缩小到单个染色体。这为研究IPC等心脏保护策略的遗传基础提供了一个绝佳的起点。尽管没有IPC在BN与SS中降低了梗塞大小，但尚不清楚SS是否可以响应IPC，并且对IPC的抵抗与内皮NO合酶（ENOS）活性的差异是否与DNA结合的蛋白质抑制剂ID2和peroxissome蛋白酶体的差异有关。 eNOS可以产生不产生或超氧化物。两者都可以调节线粒体功能，进而可以充当IPC的触发和效应子。因此，我的总体假设是，通过调节无生产和线粒体功能的基因介导了IPC心脏保护的失败/成功。因此，我建议使用此综合模型研究两个具体目的：i）确定不同的遗传背景是否负责IPC的差异性细胞和线粒体保护，ii）如果ENOS和/或其上游调节剂ID2和PPAR3是负责这种不同保护的候选基因。测试了四个假设：1）BN染色体6上的基因对于IPC是必需的，这是由更好的心脏功能和BN＆SSSSS6BN与SS中的梗塞更少的证据所证明的。 2）BN 6染色体上的基因对于IPC是必需的，这是由BN＆SSSSSS6BN与SS中更有效的线粒体功能所证明的。 3）IPC在完整心脏中对细胞和线粒体功能的保护取决于信号通路ID2-> PPAR3-> eNOS-> NO在大鼠染色体上对基因的调节6。4）在隔离心肌细胞中对细胞和线粒体功能的差异保护均取决于无可用性。 1和2的方法：各种心脏和线粒体功能，没有生产和梗塞大小完好无损，以击败心脏来评估IPC遗传确定的保护的数量和质量。 3和4的方法：在存在NOS抑制剂，无偏见或PPAR3激动剂或拮抗剂的情况下进行其他跳动心脏实验，并且ID2，PPAR3和ENOS表达的差异以及NO水平和定位。此外，在不存在或存在NO的情况下，在分离的肌细胞中测量不同的线粒体功能，以确定NO在介导IPC介导差异细胞和线粒体保护中的作用和起源。遗传工具对于研究遗传易感性的作用至关重要。将功能结果，梗塞大小和线粒体功能与IPC相关联，NO水平，蛋白质表达和基因型将使我们能够在心脏保护中定义NO和线粒体功能的信号传导途径以及与亚细胞和线粒体现象相关的condioptiation condioptiviation。该CDA标志着进一步研究遗传学在心脏保护中的作用的必不可少的基础，并且将是在VA的心血管研究中实现研究独立性的关键里程碑。